Disposable absorbent devices for the absorption of human exudates are widely used. These disposable absorbent devices typically have a mass of absorbent formed into a desired shape, which is typically dictated by the intended consumer use. In the area of a catamenial tampon, the disposable absorbent article is intended to be inserted in a body cavity for absorption of the body fluids generally discharged during a woman""s menstrual period.
There exists in the female body a complex process which maintains the vagina and physiologically related areas in a healthy state. In a female between the age of menarche and menopause, the normal vagina provides an ecosystem for a variety of microorganisms. Bacteria are the predominant type of microorganism present in the vagina; most women harbor about 109 bacteria per gram of vaginal exudate. The bacterial flora of the vagina is comprised of both aerobic and anaerobic bacteria. The more commonly isolated bacteria are Lactobacillus species, corynebacteria, Gardnerella vaginalis, Staphylococcus species, Peptococcus species, aerobic and anaerobic Streptococcal species and Bacteroides species. Other microorganisms that have been isolated from the vagina on occasion include yeasts (e.g., Candida albicans), protozoas (e.g., Trichomonas vaginalis), mycoplasmas (e.g., Mycoplasma hominis), chlamydias (e.g., Chlamydia trachomatis) and viruses (e.g., Herpes simplex). These latter organisms are generally associated with vaginitis or venereal disease, although they may be present in low numbers without causing symptoms.
Physiological, social and idiosyncratic factors affect the quantity and species of bacteria present in the vagina. Physiological factors include age, day of the menstrual cycle and pregnancy. For example, vaginal flora present in the vagina throughout the menstrual cycle can include Lactobacillus species, corynebacterium and mycoplasma. Social and idiosyncratic factors include method of birth control, sexual practices, systemic disease (e.g., diabetes) and medication.
Bacterial proteins and metabolic products produced in the vagina can affect other microorganisms and the human host. For example, the vagina between menstrual periods is mildly acidic having a pH ranging from about 3.8 to about 4.5. This pH range is generally considered the most favorable condition for the maintenance of normal flora. At that pH, the vagina normally harbors the numerous species of microorganisms in a balanced ecology, playing a beneficial role in providing protection and resistance to infection and makes the vagina inhospitable to some species of bacteria such as Staphylococcus aureus (S. aureus). The low pH is a consequence of the growth of lactobacilli and their production of acidic products. Microorganisms in the vagina can also produce antimicrobial compounds such as hydrogen peroxide and bactericides directed at other bacterial species. One example is the lactocins, products of lactobacilli directed against other species of lactobacilli.
Some microbial products may affect the human host. For example, S. aureus can produce and excrete into its environment a variety of exoproteins including enterotoxins, Toxic Shock Syndrome Toxin-1 (TSST-1) and enzymes such as protease and lipase.S. aureus is found in the vagina of approximately 16% of healthy women of menstrual age. Approximately 25% of the S. aureus isolated from the vagina are capable of producing TSST-1.
Menstrually occurring Toxic Shock Syndrome (TSS), a severe and sometimes fatal multi-system disease, is associated with colonization by S. aureus. This disease has been associated with the use of tampons during menstruation. The disease is caused by TSST-1 and other staphylococcal enterotoxins.
Symptoms of TSS generally include fever, diarrhea, vomiting and a rapid drop in blood pressure. A characteristic rash is usually present. Systemic vital organ failure occurs in approximately 6% of those who contact the disease. S. aureus does not initiate TSS as a result of the invasion of the microorganism into the vaginal cavity. Instead as S. aureus grows and multiplies, it can produce TSST-1. Only after entering the bloodstream does TSST-1 act systemically and produce the symptoms attributed to TSS.
There have been numerous attempts to reduce or eliminate pathogenic microorganisms and menstrually occurring TSS by incorporating into a tampon one or more biostatic, biocidal, and/or detoxifying compounds. For example, L-ascorbic acid has been applied to a catamenial tampon to detoxify toxin found in the vagina of the human female during menstruation. Others have incorporated monoesters and diesters of polyhydric aliphatic alcohols, such as glycerol monolaurate, as detoxifying compounds. The use of other non-ionic surfactants, such as alkyl ethers, alkyl amines and alkyl amides, has also been reported as a means of avoiding the problem of degradation by esterase (see, e.g., U.S. Pat. Nos. 5,685,872; 5,618,554; and 5,612,045).
In addition to the use of certain surfactants as detoxifying compounds, surfactants have been used to treat nonwovens for many applications involving body fluids, such as menses, to enhance wicking or the ability to rapidly distribute menses in use, so as to take advantage of the absorbency of the disposable absorbent article. Prior surfactant treatments such as ethoxylated hydrocarbons, siloxanes, and ionic surfactants have been shown to aid wicking. Although such conventional surfactants may increase wettability, they often fail to effectively reduce the viscoelasticity of menses in a manner that enhances wicking to the degree of the present invention.
It has been reported that use of specific surfactants, including alkyl polyglycosides, can not only reduce the viscoelastic properties of an insult fluid, such as menses, but also can provide surfactant properties to aid in rapidly distributing the fluid. Results were reported with alkyl polyglycosides having 8-10 carbons in the alkyl chain deposited onto the fibers of the absorbent distribution layer of an absorbent product, such as a sanitary napkin. The report suggested the use of about 0.2% to about 5% of the alkyl polyglycoside based on the total weight of absorbent material.
There continues to exist a need for agents that will effectively inhibit the production of exoproteins, such as TSST-1, from Gram positive bacteria. For such agents to become widely accepted, in addition to being effective in suppressing exoprotein production, the agent(s) should desirably also be an effective aid with regard to the distribution and/or uptake of a complex fluid on the surface of a disposable absorbent article. Such agents desirably would be substantially unaffected by the enzymes lipase and esterase and would have additional desirable properties with respect to enhancement of the wetting properties of hydrophobic polymeric materials, such as, for example, nonwoven materials commonly used as covers for absorbent articles. The selection of compounds to inhibit the production of exoproteins is not so readily apparent as some compounds, such as block copolymers of propylene oxide and ethylene oxide, can stimulate toxin production by Gram positive bacteria.
It has been found that alkyl polyglycoside compounds can inhibit the production of exoprotein(s) of Gram positive bacteria. Exposure to effective amounts of the alkyl polyglycoside(s) can inhibit the production of potentially harmful toxins, such as those produced by Staphylococcus and/or Streptococcal species. For example, the alkyl polyglycoside(s) can be utilized to inhibit the production of TSST-1, alpha toxin and/or enterotoxins A, B and C from S. aureus. The alkyl polyglycoside typically has a hydrophilic/lipophilic balance (HLB) of at least about 10 and/or an average number of carbon atoms in the alkyl chain of 8 to 12. The alkyl polyglycoside may be used alone or in combination with one or more other surfactants (e.g., myreth-3-myristate, glycerol monolaurate and/or laureth-4) and/or other additives (e.g., reducing agent(s) such as ascorbic acid, sodium bisufite, vitamin E). Such reducing agents can act as oxygen inhibiting agents and may enhance the combinations ability to reduce toxin production.
The present alkyl polyglycoside compositions are materials which, when exposed to S. aureus or other Gram positive bacteria in disposable absorbent articles, can reduce the production of exoproteins, such as TSST-1. It is also believed that the compounds in the present disposable absorbent articles are effective in combating the production of other types of bacterial toxins, in particular, alpha-toxin and Staphylcoccal enterotoxins A, B and C. In particular, the alkyl polyglycosides described herein are effective at inhibiting the production with respect to these aforementioned exoproteins when the compound is placed close to the outer surface of the disposable absorbent article. The alkyl polyglycoside may be used in combination with one or more other compounds, e.g., in combination with compounds such as myreth-3-myristate, glycerol monolaurate and/or laureth-4.
The present alkyl polyglycosides are particularly useful for inhibiting the production of bacterial exotoxins when incorporated into or on disposable absorbent articles. In particular, it has been found that incorporation of alkyl polyglycoside into at least the outer layer of a disposable absorbent article, such as a tampon, can be effective. The outer layer may be a cover over the absorbent material or may simply be the outer portion of the absorbent itself. For example, alkyl polyglycoside may be impregnated into the outermost layer, e.g., into an 1-2 mm thick outer layer of the absorbent material. Where the alkyl polyglycoside is present as part of a cover, the cover is commonly formed from a liquid-permeable material, such as a porous nonwoven sheet formed from fibers of a hydrophobic polymer. Of course, if desired, the absorbent article can also be formed with alkyl polyglycoside distributed throughout the absorbent material.
It has been found that use of alkyl polyglycosides not only can reduce the viscoelastic properties of a complex body fluid but can also provide surfactant properties to aid in rapidly distributing the body fluid. The alkyl polyglycoside is typically one with 8-14 carbons in the alkyl chain and is included in and/or on an outer surface of a disposable absorbent article, e.g., in an amount of at least about 3 wt. % and, desirably, at least about 6 wt. % based on the material weight of the outer layer of the product. It may be conveniently applied to the material in the form of an aqueous solution, e.g., containing from about 40 to about 60 wt. % water for example.
When employed as part of a catamenial tampon or otherwise introduced into a region affecting the vagina, the alkyl polyglycoside is desirably utilized in a manner and amount so as to minimize its effect on the natural vaginal flora. The present alkyl polyglycoside compositions are generally capable of substantially inhibiting the production of exoproteins from Gram positive bacteria (e.g., by reducing the amount of exoproteins produced by at least about 75% and, desirably, by at least about 90%) without creating a significant imbalance in the flora naturally present in the vaginal tract.
The alkyl polyglycoside compositions of the present invention may additionally include adjunct components conventionally found in pharmaceutical compositions in their art-established fashion and at their art-established levels. For example, the compositions may contain additional compatible pharmaceutical materials for combination therapy, such as supplementary antimicrobials, anti-parasitic agents, antipruritics, local anesthetics, or anti-inflammatory agents. As used herein the term xe2x80x9cnonwoven fabric or webxe2x80x9d means a web having a structure of individual fibers or threads which are interlaid, but not in a regular or identifiable manner as in a knitted fabric. The term also includes individual filaments and strands, yarns or tows as well as foams and films that have been fibrillated, apertured, or otherwise treated to impart fabric-like properties. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, and bonded carded web processes. The basis weight of nonwoven fabrics is usually expressed in ounces of material per square yard (xe2x80x9cosyxe2x80x9d) or grams per square meter (xe2x80x9cgsmxe2x80x9d) and the fiber diameters useful are usually expressed in microns. Basis weights can be converted from osy to gsm simply by multiplying the value in osy by 33.91.
As used herein the term xe2x80x9cmicrofibersxe2x80x9d means small diameter fibers having an average diameter not greater than about 75 microns, for example, having an average diameter of from about 0.5 to about 50 microns, or more particularly, microfibers may have an average diameter of from about 2 to about 40 microns. Another frequently used expression of fiber diameter is denier, which is defined as grams per 9000 meters of a fiber and may be calculated as fiber diameter in microns squared, multiplied by the density in grams/cc, multiplied by 0.00707. A lower denier indicates a finer fiber and a higher denier indicates a thicker or heavier fiber. For example, the diameter of a polypropylene fiber given as 15 microns may be converted to denier by squaring, multiplying the result by 0.89 g/cc and multiplying by 0.00707. Thus, a 15 micron polypropylene fiber has a denier of about 1.42 (152xc3x970.89xc3x970.00707=1.415). Outside the United States the unit of measurement is more commonly the xe2x80x9ctexxe2x80x9d, which is defined as the grams per kilometer of fiber. Tex may be calculated as denier/9.
As used herein the term xe2x80x9cspunbonded fibersxe2x80x9d refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine, usually circular capillaries of a spinneret with the diameter of the extruded filaments then being rapidly reduced as, for example, described in U.S. Pat. Nos. 4,340,563; 3,692,618; 3,802,817; 3,338,992; 3,341,394; 3,502,763; 3,502,538; and 3,542,615. Spunbond fibers are quenched and generally not tacky when deposited onto a collecting surface. Spunbond fibers are generally continuous and have average diameters frequently larger than about 7 microns, typically between about 10 and about 20 microns.
As used herein the term xe2x80x9cmeltblown fibersxe2x80x9d means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity, usually heated, gas (e.g. air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface often while still tacky to form a web of randomly disbursed meltblown fibers. Such a process is disclosed, for example, in U.S. Pat. No. 3,849,241. Meltblown fibers are microfibers which may be continuous or discontinuous and are generally smaller than about 10 microns in average diameter.
As used herein xe2x80x9cbonded carded websxe2x80x9d or xe2x80x9cBCWxe2x80x9d refers to nonwoven webs formed by carding processes as are known to those skilled in the art and further described, for example, in U.S. Pat. No. 4,488,928 which is incorporated herein by reference. Briefly, carding processes involve starting with a blend of, for example, staple fibers with bonding fibers or other bonding components in a bulky ball that is combed or otherwise treated to provide a generally uniform basis weight. This web is heated or otherwise treated to activate the adhesive component resulting in an integrated, usually lofty nonwoven material.
As used herein the term xe2x80x9cpolymerxe2x80x9d generally includes but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc., and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term xe2x80x9cpolymerxe2x80x9d shall include all possible geometrical configurations of the material. These configurations include, but are not limited to isotactic, syndiotactic and random symmetries.
As used herein, the term xe2x80x9chydrophilicxe2x80x9d means that the polymeric material has a surface free energy such that the polymeric material is wettable by an aqueous medium, i.e., a liquid medium of which water is a major component. The term xe2x80x9chydrophobicxe2x80x9d includes those materials that are not hydrophilic as defined. The phrase xe2x80x9cnaturally hydrophobicxe2x80x9d refers to those materials that are hydrophobic in their chemical composition state without additives or treatments affecting the hydrophobicity. It will be recognized that hydrophobic materials may be treated internally or externally with surfactants and the like to render them hydrophilic.
As used herein, the term xe2x80x9cporous hydrophobic polymer materialxe2x80x9d is meant to include any shaped article, provided it is porous and composed, in whole or in part, of a hydrophobic polymer. For example, the substrate may be a sheet-like material, such as a sheet of a foamed material. The sheet-like material also may be a fibrous web, such as a woven or nonwoven fabric or web. The substrate also may include hydrophobic polymer fibers, per se, or hydrophobic polymer fibers which have been formed into a fibrous web. The fibrous web desirably will be a nonwoven web, such as, but not limited to, a meltblown web or a spunbonded web. The substrate also may be a laminate of two or more layers of a sheet-like material. For example, the layers may be independently selected from the group consisting of meltblown webs and spunbonded webs. However, other sheet-like materials may be used in addition to, or instead of, meltblown and spunbonded webs. In addition, the layers of the laminate may be prepared from the same hydrophobic polymer or different hydrophobic polymers.
The term xe2x80x9chydrophobic polymerxe2x80x9d is used herein to mean any polymer resistant to wetting, or not readily wet, by water, i.e., having a lack of affinity for water. Examples of hydrophobic polymers include, by way of illustration only, polyolefins, such as polyethylene, ethylene-propylene copolymers, and ethylene-vinyl acetate copolymers; styrene polymers, such as poly(styrene), poly(2-methylstyrene), styrene-acrylonitrile copolymers having less than about 20 mole-percent acrylonitrile, halogenated hydrocarbon polymers, such as poly (tetrafluoroethylene), tetrafluoroethylene-ethylene copolymers, poly (trifluoroethylene); vinyl polymers, such as poly (vinyl butyrate), and poly (methacrylonitrile); acrylic polymers, such as poly (n-butyl acetate), poly (ethyl acrylate), and polyesters, such as poly (ethylene terephthalate) and poly (butylene terephthalate). The hydrophobic polymer also may contain minor amounts of additives as is customary in the art. For example, the hydrophobic polymer may contain pigments, delustrants, antioxidants, antistatic agents, stabilizers, oxygen scavengers, and the like.
The term xe2x80x9cpolyolefinxe2x80x9d is used herein to mean a polymer prepared by the addition polymerization of one or more unsaturated monomers which contain only carbon and hydrogen atoms. Examples of such polyolefins include polyethylene, polypropylene, poly (1-butene), poly (2-pentene), and the like. In addition, such term is meant to include blends of two or more polyolefins and random and block copolymers prepared from two or more different unsaturated monomers. Because of their commercial importance, the most desired polyolefins are polyethylene and polypropylene.
As already stated, the coated porous substrate may include hydrophobic polymer fibers. Such fibers are substantially uniformly coated with a hydrophilic polymeric material. As an example, the hydrophobic polymer fibers may be polyolefin fibers. For example, the polyolefin fibers may be polyethylene or polypropylene fibers. The hydrophobic polymer fibers generally may be prepared by any known means. As a practical matter, however, the fibers usually will be prepared by a melt-extrusion process and formed into a fibrous web, such as a nonwoven web. The term xe2x80x9cmelt-extrusion processxe2x80x9d as applied to a nonwoven web is meant to include a nonwoven web prepared by any melt-extrusion process for forming a nonwoven web in which melt-extrusion to form fibers is followed by web formation, typically concurrently, on a foraminous support. The term includes, among others, such well-known processes as meltblowing, coforming, spunbonding, and the like.
As used herein, the term xe2x80x9cpledgetxe2x80x9d means a compress used to apply pressure or press upon a body part.
The term xe2x80x9csurfacexe2x80x9d and its plural generally refer herein to the outer or the topmost boundary of an object.
The term xe2x80x9cdurablexe2x80x9d as used herein with reference to a coating of a hydrophilic polymeric material on the porous substrate means that the coated porous substrate remains wettable after at least three exposures to an aqueous medium, such as water, saline, and urine and other body fluids. One procedure for evaluating durability when the porous substrate is a fibrous web is a modified run-off test followed by washing and drying (a wash/dry cycle). The fibrous web typically will remain wettable for at least five cycles of exposing, washing, and drying. Desirably, the coated porous substrate will remain wettable after being subjected to at least ten cycles. The run-off test (exposure) and wash/dry procedure are described in U.S. Pat. No. 5,258,221, which is incorporated herein by reference.
As used herein, the term xe2x80x9chydrophilic polymeric materialxe2x80x9d means that the polymeric material has a surface free energy such that the material is wettable by an aqueous medium. That is, an aqueous medium wets the hydrophilic polymeric material with which the porous substrate is coated. For example, the surface free energy of the hydrophilic polymeric material may be at least about 50 dynes/cm. As another example, the surface free energy of the hydrophilic polymeric material may be in a range of from about 50 to about 72 dynes/cm.
The term xe2x80x9caqueous mediumxe2x80x9d is used herein to mean any liquid medium of which water is a major component. Thus, the term includes water per se and aqueous solutions and dispersions. For example, the aqueous medium may be a liquid bodily discharge, such as urine, menses and saliva.
As used herein, the term xe2x80x9cwettablexe2x80x9d and variations thereof means wettable by an aqueous medium, i.e., the aqueous medium spreads over the surface of a substrate. The term is used interchangeably with the term xe2x80x9cwettable by waterxe2x80x9d and variations thereof and has the same meaning.
As used herein, the phrase xe2x80x9ccomplex body fluidxe2x80x9d is intended to describe a fluid generally characterized as being a viscoelastic mixture including specific components having generally inhomogeneous physical and/or chemical properties. It is the inhomogeneous properties of the specific components that often challenge the efficacy of absorbent articles in the handling of complex fluids, such as, for example, blood, menses, loose passages, nasal discharges and the like. In contrast with complex fluids, simple fluids, such as, for example, urine, physiological saline, water and the like, are generally characterized as being Newtonian and including one or more components having generally homogeneous physical and/or chemical properties. As a result of having homogeneous properties, the one or more components of simple fluids behave substantially similarly during absorption or adsorption.
As used herein, the phrase xe2x80x9cabsorbent articlexe2x80x9d refers to devices which absorb and contain body fluids, and more specifically, refers to devices which are placed against or near the skin to absorb and contain the various fluids discharged from the body. The term xe2x80x9cdisposablexe2x80x9d is used herein to describe absorbent articles that are not intended to be laundered or otherwise restored or reused as an absorbent article after a single use. Examples of such disposable absorbent articles include, but are not limited to: health care related products including bandages and tampons such as those intended for medical, dental, surgical and/or nasal use; personal care absorbent products such as feminine hygiene products (e.g., sanitary napkins, panty liners and catamenial tampons), diapers, training pants, incontinent products and the like, wherein the inhibition of the production of exoproteins from Gram positive bacteria would be beneficial.